The Apostle of Allah ﷺ said to him: Lead your people in prayer. I said: Messenger of Allah. I perceive something (disturbing) in my soul. He (the Holy Prophet) asked me to draw near him and making me sit down in front of him he placed his hand on my breast between my nipples. and then, telling me to turn round, he placed it on my back between my shoulders. He then said: Act as an Imam for your people. He who acts as Imam of the people, he must be brief, for among them are the aged, among them are the sick, among them are the weak, and among them are the people who have business to attend. But when any of you prays alone, he may pray as he likes. (Using translation from Muslim 468a)   

أَنَّ النَّبِيَّ ﷺ قَالَ لَهُ أُمَّ قَوْمَكَ فَقُلْتُ يَا رَسُولَ اللهِ إِنِّي أَجِدُ فِي نَفْسِي شَيْئًا قَالَ ادْنُهْ فَأَجْلَسَنِي بَيْنَ يَدَيْهِ ثُمَّ وَضَعَ كَفَّهُ فِي صَدْرِي بَيْنَ ثَدْيِيَّ ثُمَّ قَالَ تَحَوَّلْ فَوَضَعَهُمَا فِي ظَهْرِي بَيْنَ كَتِفِيَّ ثُمَّ قَالَ أُمَّ قَوْمَكَ فَمَنْ أَمَّ قَوْمًا فَلْيُخَفِّفْ فَإِنَّ فِيهِمُ الْكَبِيرَ وَإِنَّ فِيهِمُ الصَّغِيرَ وَإِنَّ فِيهِمُ الْمَرِيضَ وَإِنَّ فِيهِمْ ذَا الْحَاجَةِ فَإِذَا صَلَّى أَحَدُكُمْ فَلْيُصَلِّ كَيْفَ شَاءَ